Fix locale-dependent float printing in GGUF metadata (#17331)

* Set C locale for consistent float formatting across all binaries.

* Add C locale setting to all tools binaries

Add std::setlocale(LC_NUMERIC, "C") to all 16 binaries in the tools/
directory to ensure consistent floating-point formatting.

* Apply suggestion from @JohannesGaessler

---------

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>

tools/completion/completion.cpp

@@ -6,6 +6,7 @@
 #include "llama.h"
 #include "chat.h"
 
+#include <clocale>
 #include <cstdio>
 #include <cstring>
 #include <ctime>
@@ -84,6 +85,8 @@ static void sigint_handler(int signo) {
 #endif
 
 int main(int argc, char ** argv) {
+    std::setlocale(LC_NUMERIC, "C");
+
     common_params params;
     g_params = &params;